1. Field of the Invention
The present invention relates to a system for feeding the power to a telephone terminal/terminals connected to a LAN (Local Area Network).
2. Description of the Related Art
In recent years, the so-called downsizing has been rapidly developed in the information processing field. For facilitating the downsizing, technology of LAN's has been developed for achieving distributed processing or horizontal distributed processing using a plurality of work stations or personal computers. Simultaneously, technology of LAN telephone terminals adapted for the LAN environment has also been developed. In this case, it is important to realize a power feeding system for the LAN telephone terminals.
Specifically, in transmission lines forming the LAN environment, data signals are flowing. Thus, it is difficult to use those transmission lines as power feed lines as in the public network. In particular, this is almost impossible in Ethernet LAN's wherein Manchester codes having no DC components are used as transmission codes. As is known in the art, the Manchester code is a code whose polarity is inverted at the center of a bit sequence so as to define a logical value of 1 or 0 by a direction of the inversion. Under the circumstances, the telephone terminals in the LAN receive the power from the commercial power source via AC adapters, respectively.
In this technique, however, since the respective telephone terminals receive the power from the commercial power source via the AC adapters, installation of the telephone terminals is troublesome. Further, every time an installed position of the telephone terminal is changed, an operator is required to make the installed position thereof clear relative to the network, thereby lacking in portability.